The basic premise of this proposal is that emotion is comprised of a number of components which may utilize different brain systems. These components include: affective experience (or "subjective feelings"), expressive behavior, cognitive appraisal, somatic arousal, and goal-directed activity (e.g., Plutchik, 1984). The proposed research will focus on affective experience, in particular its hedonic (i.e., pleasant/unpleasant) aspect, and its relation to expression. The unique feature of this research is the use of intrinsically hedonic and minimally cognitive stimuli to elicit affective responding in brain-damaged patients. The framework for our project emanates from the literature on laterality and emotion. Although much research has shown that the two sides of the brain differ in their involvement in emotion, many questions remain, perhaps the most important being whether they differ with respect to hedonic valence. The experimental subjects will be 16 right brain-damaged and 26 left brain- damaged patients with unilateral frontal lobe lesions from cerebrovascular pathology. Sixteen matched normal controls will also serve as subjects. Hedonic experience will be assessed through subjects' ratings of pleasant and unpleasant odors. Expression will be assessed through both spontaneous and "prompted" facial displays in response to the odors, which will be evaluated by naive judges from videotaped records. Our objective is to determine whether patients with right- and left-sided brain damage differ in hedonic experience, facial response to hedonic stimuli, and the relationship between experience and expression. This study will be the first to focus on hedonic experience and expression via olfactory stimulation in a brain-damaged population. Our work is based on the belief that understanding the neurological bases of emotion requires a research strategy in which each component can be assessed independently of the others. If this preliminary research reveals patient group differences, a proposal for a more elaborate study will be submitted, in which additional components of emotion, e.g., arousal, are systematically compared within the same group of brain-damaged patients.